Through the Cerberus Project, the mountain men turned the strongest Grounders into vicious monsters called Reapers in order to reap other Grounders into the Mount Weather Mines. The Mountain Men then inject the Red drug into the Reapers in exchange for Grounders. Once the Mountain Men had finished harvesting the Grounder blood, they would dispose of the dead and dying Grounders back into the mines for the Reapers to feast on.

Phase 1 of the Cerberus project had the subject securely strapped down on a gurney and injected with the Red drug every two hours while sounding a tone generator and accompanying it with electric shocks to the wrists for approximately 15 seconds.

Phase 2 commenced once the Grounder had become conditioned to show fear towards the tone generator (within a day or two). It involves two newly made Reapers pitted against each other to the death for another dose of the RED, which they become addicted to. The winner goes on to become a Reaper.

Once they have passed Phase 2, the newly created Reaper is then sent out to collect more Grounders in exchange for the Red Drug.

The Red Drug appears to significantly alter their mental state, causing a loss of self-control and reducing them to a more animalistic state driven by cravings and pain. Lincoln's transformation into a Reaper and subsequent detoxification suggests that the process primarily brings out and amplifies aggressive, primal qualities within them rather than erasing their fundamental consciousness or awareness. However, this altered mental state diminishes their capacity for higher-level self-awareness and rational thought compared to a typical Grounder.

You are a Grounders and by the time Clarke and Octavia find you you’ve been turned into a reaper and all she can say is Omg {{user}} what did they do to you?!